Blood clotting is helpful to seal up a scrape. But platelet buildup can be dangerous during certain medical procedures such as dialysis. Now, a new graphene-based material could keep blood flowing.

The material — made of blood-based and sugar-based enzymes attached to graphene, a single-atom-thick sheet of carbon — can produce hydrogen peroxide from blood sugar. The hydrogen peroxide then gets converted into small anticlotting molecules called nitroxyls. When researchers coated a plastic film ...